NAIROBI, Kenya — On Sunday, gunmen attacked two churches in Garissa, a city in northeastern Kenya. At least 17 people were killed, and more than 40 wounded. The Somali militant group al-Shabab and its supporters have been blamed for other attacks in Kenya.

Four gunmen attacked the African Inland Church in Garissa on Sunday morning. The shooters were masked in balaclavas, regional police chief Philip Ndolo told Reuters. They entered the church after throwing two grenades inside. Two grenades also exploded in a nearby Roman Catholic Church. Two police are among the dead.

Qadr, a Garissa resident, is looking for his housekeeper. He fears she may be a victim of the attack.

“She’s not around, I’ve been looking for her, I don’t even know if she was one of those people who died,” he said

Garissa is a city in northeastern Kenya populated by ethnic Somalis. Garissa is located 100 kilometers from Dadaab, home to what is often considered the largest refugee camp in the world. Dadaab has received a steady stream of Somalis fleeing the civil war in their country.

Kenyan troops invaded southern Somalia last October, joining African Union troops in a battle against the al-Qaida-linked al-Shabab Islamists. Since the Kenyan invasion, a wave of grenade attacks and kidnappings have beleaguered Kenya. Analysts believe al Shabaab or its supporters may be behind these attacks.

Earlier this week, four foreign aid workers from the Norwegian Refugee Council were kidnapped in the Dadaab camp. Their Kenyan driver was killed.

In the last year several aid workers have been kidnapped from Dadaab. Many international NGOs and humanitarian groups have since scaled down their operations in the camp.